Spin the blade around so that it is reversed, but at an angle so the snow pushes off to one side. Drive backwards pushing the snow in reverse.
Set the top link so that the blade does not rise up or cut down (that may take a bit of trial and error) but the blade should be pretty much plumb vertical when you are done adjusting the top link. Also make sure the blade is level side to side, when rotating a blade and setting it on an angle often one side will end up higher than the other. Adjust your turnbuckle on one of your lower link arms to compensate for this issue to get it level.
When you plow, if set properly, it should not dig or float. It should simply push the snow to one side. If you do not want it to tear up the gravel then don't lower it all the way down, your 3pt should allow you to hold the blade just above the gravel. If the gravel is smooth BEFORE winter sets in (HINT, HINT . . . groom the driveway & remove the potholes, washboards, tire ruts, etc before the snow falls) then you should not have any real problems if you set the blade about an inch above the surface.
When using a rear blade, you are well advised to plow your drive before the snow is as deep as the blade is tall. That may require you to get out and plow the drive a couple times during heavy storms, but it is easier than trying to plow when the snow comes over the top of the blade and you can't see the blade/ground well due to the spill over.